package mmmmk;

import java.util.Scanner;

public class poooo {
	public static void main(String[] args){
	int[] a = new int[5];
	Scanner sc = new Scanner(System.in);
	while(sc.hasNext()){
	String str = sc.next();
	try{
		if(str.equals("arr"))
		{
			int b = sc.nextInt();
			if(b>4)
				System.out.println(a[b]);
		}
		if(str.equals("null")){
			throw new NullPointerException();
		}
		if(str.equals("cast")){
			Object x = new String();
			System.out.println((Integer)x);
		}
		if(str.equals("num")){
			String b = sc.next();
			int n = Integer.parseInt(b);
		}
		else
			break;
		}
	catch(Exception e){
		System.out.println(e);
	}
	}
}
}
